This invention relates to a kit for simply analyzing fuel oil for its catalyst component content.
Fuel oil for marine engines has commonly been a mixture of light gas oil and long and short residuums from atmospheric and vacuum distillations, respectively. However, in order to meet growing demand for light gas oil and save the fuel cost, there is an increasing tendency in the art to squeeze out an additional percentage of light oil from the long and short residuums by thermal or catalytic cracking or other technique and then mix the thickened residue with light gas oil or the like as fuel for marine engines.
The mixed fuel thus formed is high in specific gravity and viscosity, with by far the greater carbon residue than the ordinary heavy fuel oil C.
The residue after the extraction of light gas oil by catalytic cracking is generally known as fluid catalytic cracking (FCC) oil. It contains hard microspheroids of a silica-alumina catalyst, ranging in particle size from 5 to 80.mu., as the catalyst for catalytic cracking. The fuel oil containing such hard particles is believed responsible for the unusual wear of piston rings and cylinder liners of diesel engines. There are instances in which fuels incorporating FCC oils with Si contents of 300 to 3000 ppm caused rapid wear of the rings and liners in diesel engines. If this premature wear is to be avoided, it will be necessary to know if any FCC oil is incorporated in the fuel and, if so, remove it or reject the fuel oil.
A conventional practice for analyzing fuel oil for the presence of the silica-alumina catalyst in the FCC oil as fuel has been to ash the questionable fuel oil once, dissolve the ash in a solvent, and subject the resulting solution to a colorimetric analysis for silica. The fuel oil ashing is conducted in conformity with the procedure of Japanese Industrial Standards K-2272 (Testing Method for Determination of Ash Contents in Crude Oils and Petroleum Products). The procedure consists in gradually carbonizing the fuel by weak heating until the oil ceases to give off any more volatile matter, and then reducing the resultant to ash by heating at about 800.degree. C. Thus, complete ashing takes about two days, or too much time to meet field requirements.
In order to eliminate the disadvantage, we have already proposed in Japanese Patent Application No. 13865/1979 a method for field analysis to determine the catalyst component content in fuel oil in a simple and quick way. The previous invention was perfected with the view to analyzing the fuel oil to be supplied to a ship at any port of call for her engines conveniently and promptly to see if it contains the FCC oil and avoiding the use of any fuel oil containing the same and thereby preventing troubles of the diesel engines and the like. To attain the end, that invention comprises dissolving a sample amount of fuel oil in an organic solvent, filtering the solution and separating out the residue, i.e., the silica-alumina catalyst, dissolving its main component silica into fluoric acid, and then subjecting the resulting solution to colorimetric determination of its Si ion content. Without the need of ashing the residue, the method of the invention is advantageous over the conventional technique in that it permits simpler and quicker determination of the silica content and easier detection of the FCC oil present in the fuel. The method is, therefore, effectively applicable to the evaluation of a given fuel (usually fuel oil C), its adequacy or inadequacy for given thermal engines, such as diesels or boilers.
However, there has been no equipment available for the field analysis in conformity with the method of the invention.